What does the term isolated ducts mean? What is its significance?
In the case of a low obstruction of the common bile duct, as would typically occur in the setting of a pancreatic head mass or common bile duct calculus, the right and left systems still communicate. Either a single right-sided biliary drain or a single left-sided biliary drain can be used to decompress the entire biliary tree. If the level of obstruction is higher, as might occur with cholangiocarcinoma or sclerosing cholangitis, this might not be the case, and some ducts may not communicate with others—they are “isolated” from one another. This is one reason that highlights the importance of obtaining cross-sectional imaging prior to biliary drainage. If only one ductal system is dilated, this information helps to determine the access site (left-sided drainage vs. right-sided drainage). Patients who have multiple isolated portions of the biliary tree will have some ducts that remain undrained if only a single catheter is placed. These patients may require more than one drainage catheter to treat infection, pruritus, or hyperbilirubinemia.